Magnetic coupling for multiple contact relays



A. GUNST Feb. 25, 1969 MAGNETIC COUPLING FOR MULTIPLE CONTACT RELAYS Filed Jan. 26, 1967 FigJ) (F012 Fig.2)

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RI GHT CON TAC T5 CENTER LEFT A. l/NST INVENTOR ATTORNEY United States Patent 3,430,167 MAGNETIC COUPLING FOR MULTIPLE CONTACT RELAYS Alfred Gunst, Stuttgart-Zuflenhausen, Germany, assignor to International Standard Electric Corporation, New

' York, N.Y., a corporation of Delaware Filed Jan. 26, 1967, Ser. No. 612,008 Claims priority, application Germany, Feb. 16, 1966,

St 24,993 US. Cl. 335-152 3 Claims Int. Cl. H01h 1/66, 51/00 ABSTRACT OF THE DISCLOSURE Improved magnetic circuits or returns are provided for multiple contact relays. The circuits in preferred embodiments are formed by metal plates having cross-sectional areas which are shaped to present different magnetic reluctances in different parts. The difierent reluctances adjust the magnetic coupling to a different value for each of the individual contacts. Relays constructed in accordance with the principles of the invention have reduced switching speeds and at the time require less power for actuation.

This invention relates to multiple contact relays and particularly to improved magnetic coupling for such relays.

Multiple or ganged relays with contacts arranged in reed tubes and provided with magnetic returns are well known. For example, the German printed application (DAS) 1,090,321 contains a description of a reed contact relay in which contacts have their terminal ends arranged side by side in plane levels and have a magnetic return associated with each level. The magnetic returns are formed by bending a fiat sheet metal strip supporting the excitation winding and are placed fiat onto the terminals of the contact springs, with their outwardly bent ends maintaining a proper electrical insulation.

Moreover, reed contact relays are known by the German printed applications (DAS) 1,065,938 and 1,117,760, in which relays are provided with similar magnetic return or restoring sets like the relay shown in DAS 1,090,321.

Multi-contact reed relays with a rectangular coil crosssection, of the type described in the German printed application (DAS) 1,065,938, however, have the draw-back that the electrical values of the built-in reed contacts depend on the position of the contacts within the coil (edge or centre position, respectively), due to the magnetic field, resulting from ferro-magnetic parts, e.g. reed contacts. This disadvantage cannot be avoided in any of the aforementioned constructions.

Furthermore, a reed contact relay with a defined actuating sequence of its contacts is known from the German printed application (DAS) 1,078,692. In this arrangement a known magnetic shunt or restoring device is used, its bent ends being slotted like a comb. The teeth thereby obtained are facing the terminals of the contacts with a defined space or a defined surface, respectively, to form the individual magnetic resistance. This arrangement is suitable to provide arbitrarily determined actuating sequences through reed contacts of a type defined.

It is the primary object of the present invention to reduce in a reed contact multiple or ganged relay the scattering zone of the electrical values and the switching periods of the individual contacts and to obtain a decrease of the actuating power. This is achieved according to the invention by compensating the magnetic field, resulting 3,430,167 Patented Feb. 25, 1969 from ferro-magnetic parts at coils having a rectangular cross-section. The reed contacts, located in the centre of the excitation coil, are magnetically more firmly coupled by suitable shaping of the magnetic returns and/or their outward directed bends, than the reed contacts located in the marginal zone of the excitation coil.

The invention also may be said to relate to a reed contact multiple or ganged relay with a rectangular coil cross section, in which the reed contacts are arranged in a staggered twin-row with magnetic returns associated in common with several contacts of the relay. The magnetic returns are placed in parallel with the reed tubes within the range of an excitation winding to enclose the reed tubes, and are bent adjacent to the front sides of the excitation winding in the direction of the terminals of said reed tubes. The ends of the magnetic return with their bent portions provide a different magnetic coupling for each of the individual contacts.

According to one embodiment of the invention the outwardly directed bends of the magnetic returns or shunts are rounded convex and arch-shaped.

According to a further embodiment of the invention the magnetic returns or shunts are formed as small strips which only cover the reed contacts, located in the centre of the excitation coil.

The reed contact multiple relay according to the invention shows various advantages. For example, a reduction of the switching period tolerances and the actuating powers result from narrowing the scattering zone of the electric values.

The invention is described with the aid of accompanying drawings wherein:

FIG. 1 shows a reed contact multiple or ganged relay with magnetic returns known per se,

FIG. 2 shows a reed contact multiple or ganged relay with magnetic returns according to a first embodiment of the invention,

FIG. 3 shows a reed contact multiple or ganged relay with magnetic returns according to a further embodiment of the invention, and

FIG. 4 shows a diagram representing the flux, required to pull up the individual contacts at difierent returns according to FIGS. 1, 2 and 3.

For the sake of simplicity in the presentation, only nine reed contacts within a relay are shown in the FIGS. 1 to 3. The same principles apply, of course, for relays with more than nine reed contacts.

In FIG. 1, numbers 11 and 12 designate magnetic shunts, associated with a row of reed contacts, arranged staggered within the excitation winding. The shunt or magnetic return 11 covers the reed contacts 1, 3, 5, 7 and 9 while the magnetic return 12 covers reed contacts 2, 4, -6 and 8 (not visible on the drawing). The magnetic returns 11 and 12 are placed within the range of the excitation winding, in parallel to the reed contacts, bent adjacent to the front sides of the excitation winding in the direction of the terminals of the reed contacts and bent again towards the outside approximately at the level of the terminals of the associated reed contacts 1 to 9 or 2 to 8, respectively.

The bent portions 13 and 14, directed to the outside, have a rectangular shape of familiar design. The curve shown in FIG. 4 relating to the reed contacts in FIG. 1 demonstrates the disadvantages of this shape of a magnetic return. It may be gathered from the curve that reed contacts located in the centre of the excitation coil require a magnetic flux higher by approximately 40% than contacts located at the marginal zone within the excitation coil.

The magnetic returns 11' and 12' shown in FIG. 2 include outwardly directed portions 13' and 14' having a rounded or arched form. The curve in FIG. 4, pertaining to the arrangement shown in FIG. 2 demonstrates that a substantial reduction of the scattering zone of the electric values is obtained by this form of bendings 13' and 14' of the magnetic returns 11 and 12'.

Now the reed contacts located in the centre of the excitation coil can be pulled up by a flux only approximately 30% higher than that for the contacts located in the marginal zone within the excitation coil. At the same time the total power required for the relay drops by approximately In the relay shown in FIG. 3 the magnetic returns 11 and 12" are made as small strips which cover only the reed contacts located in the centre of the excitation coil, e.g. contacts 3, 4, 5, '6, 7. The outwardly directed bendings 13 and 14" are made in a way known per se. As may be gathered from the respective curve in FIG. 4, another considerable reduction of the scattering zone of the electric values is obtained due to the change in shape of the magnetic returns 11" and 12". The reed contacts, located in the centre of the excitation coil, require only approximately 10% more magnetic flux to pull up the contacts, than for those contacts located in the marginal zone. Moreover, a power saving for the relay of approximately 30% is achieved, compared to a relay with magnetic returns according to FIG. 1.

Not shown are further constructions of the magnetic returns 11 and 12 and their bendings 13 and 14, respectively, which can be obtained e.g. by a combination of the arrangements shown in FIGS. 2 and 3.

While the principles of the invention have been described above in connection with specific apparatus and applications, it is to be understood that this description is made only by way of example and not as a limitation on the scope of the invention.

What is claimed is:

1. A multiple contact reed relay, comprising a plurality of reed contacts, arranged with their terminals, in a row,

magnetic returns placed in parallel with the common reed contacts to magnetically link the reed contacts,

said magnetic returns including first portions parallel to and covering the reed contacts and second portions parallel to and covering the terminals of said reed contacts,

said second portions being spaced closer to the terminals of the contacts than the first portions are to the contacts,

said second portions being shaped to compensate a magnetic field applied to the reed contacts,

said second portions effectively linking the terminals of the contacts near the center of the row more firmly than the terminal near the ends of the row.

2. A multiple contact reed relay as claimed in claim 1,

in which the second portions are arch-shaped to provide the compensation of a magnetic field.

3. A multiple contact reed relay as claimed in claim 1,

in which the second portions of the magnetic returns are in the shape of small strips to cover only reed contact terminals in the center of the row and leaving exposed the contact terminals at the ends of the row.

References Cited UNITED STATES PATENTS 3,030,468 4/1962 Donceel et al. 335152 3,188,424 6/1965 Else et a1. 335-152 BERNARD A. GILHEANY, Primary Examiner.

ROY N. ENVALL, JR., Assistant Examiner. 

